1. Field of the Invention
The invention relates to a method and apparatus for surveillance of a bow-type continuous casting plant, in particular of a steel bow-type continuous casting plant, where a curved strand exiting from the strand guiding provision is straightened in a straightening provision.
2. Brief Description of the Background of the Invention Including Prior Art
Two types of curved continuous casting apparatus are known. One type relates to curved continuous casting plants, where the strand is cast in a curved mold and is straightened in a straightening aggregate after redirection into a horizontal direction. A second type relates to curved continuous casting plants, where the strand is cast in a straight line mold, is redirected in a bending aggregate into a circular curve path and after reaching of a horizontal direction the strand is straightened out in a straigtening provision. A standstill of the strand can occur in each of the two systems based on interruptions of the operation, that is the strand remains standing still for a certain short time in the apparatus until the interruption is eliminated. In addition, it may become necessary to substantially reduce the withdrawal speed of the strand and the casting speed for certain times, for example in cases where it is desired to change the cross-section of the strand without interruption of the continuous casting process. Such standstill or reduction of the withdrawal speed of the strand causes a solidification of the strand inside of the apparatus such that increased directional forces become necessary for bending or, respectively, straightening of the strand based on the increased stiffness of the strand.
In case the strand remains too long in the apparatus, then heavy damages can be caused to the apparatus upon following withdrawal of the excessively cooled strand and in particular the guide rolls and the straightening aggregate can become damaged, and such damage is usually associated with correspondingly long breakdown times and with high costs for repair of the damage.